pyp5js

pyp5js: drawing with Python 3

Processing ideas and Python 3 together with P5.js in the browser, using Transcrypt.

Python 3 drawing in the web 🐍 🐍 🐍 Try it here!

pyp5js covers all the methods, variables and event handlers listed in the p5.js API documentation. Here’s an example of a valid Python code using p5.js API:

def setup():
    createCanvas(200, 200)

def draw():
    background(200)
    diameter = sin(frameCount / 60) * 50 + 50
    fill("blue")
    ellipse(100, 100, diameter, diameter)

Examples

Click here to see a list of examples generated with pyp5js.

Installation

This project requires Python 3 and is now on PyPI, so you can install it with pip or pip3, depending on your environment:

$ pip install pyp5js

(You might have to install setuptools first, if it’s not already installed)

Quickstart

Since you’ll be writing Python code and then generating the correspondent P5.js code from it, pyp5js provides a web application interface to help you generate the files.

So, to start the application, you’ll have to run:

$ pyp5js serve

Then point your browser to http://localhost:5000/ and create a new sketch via the browser by filling the form with the name of your sketch. This command will compile the sketches on the fly, so after changing/saving the sketch file, you just need to reload the page on your browser. It’ll also guide you on which file you have to edit the Python code and how to see it running after you save it.

pyp5js will create a new directory in your home called sketchbook-pyp5js. If you don’t want to save your sketch in this default directory, you can set the environment variable SKETCHBOOK_DIR to point to the directory you want to use. Or you can also run the serve command as:

$ SKETCHBOOK_DIR='~/my-custom-sketchbook' pyp5js serve

Now, have fun =]

Command Line Interface

So, to start a new sketch, you’ll have to run:

$ pyp5js new my_sketch

This command will create a directory with the following code structure using p5.js 1.0.0:

~ my_sketch/
  ~ static /
  ~ target /
  - index.html
  - my_sketch.py

The index.html is prepared to display your sketch, so you’ll have to keep it open in your browser (I really advise you to use Firefox) to see results from the code you’ll add to my_sketch.py.

To see your app on your browser you’ll need to run a Web server (opening the “index.html” file directly won’t work since it is disabled by default) - we packaged it already for you, just run:

$ pyp5js serve

If you just want to compile your code (without running the Web server) there’s the compile command:

$ pyp5js compile my_sketch

If you’re lazy like me, you can use the monitor command instead of the previous one. The command will monitor your sketch directory and keep track of any changes on any .py files. When it notices a new change, it automatically runs the compile process for you:

$ pyp5js monitor my_sketch

You can also use the --monitor option within the new command by running:

$ pyp5js new my_sketch --monitor

All of the command-line interface methods have a few optional arguments, such as specifying the sketch directory. You can check them by running:

$ pyp5js --help

# or also

$ pyp5js new --help

Known issues, differences to the Processing.Py and P5.js ways of doing things and limitations

• Remember to use P5.js method names & conventions for most things.

• There are no Py.Processing with context facilities for push/pop or beginShape/endShape.

• There are no PVector objects, with their nice syntatic operator overloaded sugar - use p5.Vector with createVector() and P5.js conventions … for now…

• For the mouseWheel() event funtion, use def mouseWheel() with NO parameters, then, inside the function, the magic event.delta will have a value equivalent to the one returned by Java&Python Mode’s event.getCount().

• At this point, it is a known limitation that you have to “declare” global variables before setup() and draw(), maybe using name = None, as they can’t be created inside methods.

• Not all Python libs are available when using Transcrypt because they required a JS-version to be enabled. In this link you can take a look in all modules Transcrypt enables.

How can I contribute?

More details here.

References

This project started from a proof of concept based in Axel Tanner’s “Transcrypt & p5js” blogpost. The source code in this Github repo.

The Pyodide interpreter was implemented based on Luca Damasco’s experiment supported by COSA (The Clinic for Open Source Arts) at the University of Denver College of Arts and Sciences.

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